To cite simPH in publications use:

Christopher Gandrud (2015). simPH: An R Package for Illustrating Estimates from Cox Proportional Hazard Models Including for Interactive and Nonlinear Effects. Journal of Statistical Software, 65(3), 1-20. URL http://www.jstatsoft.org/v65/i03/.

Corresponding BibTeX entry:

  @Article{,
    title = {{simPH}: An {R} Package for Illustrating Estimates from
      Cox Proportional Hazard Models Including for Interactive and
      Nonlinear Effects},
    author = {Christopher Gandrud},
    journal = {Journal of Statistical Software},
    year = {2015},
    volume = {65},
    number = {3},
    pages = {1--20},
    url = {http://www.jstatsoft.org/v65/i03/},
  }